疏水改性聚丙烯酰胺对原油组分界面扩张流变性质的影响

利用悬挂滴方法研究了疏水改性聚丙烯酰胺(HMPAM)对胜利采油厂高温高盐油藏采出原油中酸性活性组分和沥青质界面膜扩张流变性质的影响,考察了不同活性组分浓度条件下的界面扩张流变行为.实验结果表明:1750mg·L-1HMPAM能够在界面上形成网络结构,界面扩张模量数值高达100mN·m-1左右;油相中的酸性组分随着老化时间增加吸附到界面上,与HMPAM分子的疏水改性部分形成聚集结构,一方面通过快速的扩散交换过程大大降低扩张模量,另一方面通过与疏水改性部分的相互作用加强HMPAM分子间的缔合强度,增强网络结构的弹性.沥青质分子尺寸相对较大,分子间存在氢键等较强的相互作用,造成沥青质界面聚集体和HMPAM形成的网络结构共同决定界面膜性质,混合膜的扩张模量较单独HMPAM体系仅略有降低.

Effect of Hydrophobically Modified Polyacrylamide on Interfacial Dilational Rheological Properties of Crude Oil Components

The effect of hydrophobically modified polyacrylamide (HMPAM) on the dilational rheological properties of interfacial films containing acidic components or asphaltenes in petroleum crude oil was investigated by drop shape analysis method. The influence of surface-active component concentration on the dilational rheological behavior was investigated. Experimental results show that the dilational modulus is approximately 100 mN·m^-1 for a 1750 mg·L^-1 HMPAMsolution. This is due to the formation of an interfacial structure by a hydrophobic interaction among HMPAM molecules. As the interfacial film ages, the acidic component molecules adsorb onto the interface and form mixed complexes with the hydrophobic parts of the HMPAMmolecules. These interactions reduce the dilational modulus by a fast exchange process and the elasticity of the structure improves because of an enhanced hydrophobic interaction among the HMPAMmolecules. For asphaltenes, the nature of the interfacial film is controlled by both the structure of HMPAMand the interfacial complex formed by pure asphaltene molecules because of their relatively larger molecular sizes as well as their strong intermolecular interactions, which leads to a slight decrease in the dilational modulus compared with the pure HMPAMsystem.